Controlled medical injection apparatus



Aug. 22, 1967 L.. K. THOMPSON m 3,336,925

CONTROLLED MEDICAL INJECTION APPARATUS Filed July 9, 1965 FIG. 2

I N VEN TOR. Lawrence K. Thompson, III

ATTORNEY United States Patent 3,336,925 CONTROLLED MEDICAL INJECTION APPARATUS Lawrence K. Thompson III, 3815 Tremont Drive, Durham, N.C. 27705 Filed July 9, 1965, Ser. No. 470,816 9 Claims. (Cl. 128-218) This invention relates to a motor driven medical injection apparatus, and more particularly, to improvements in automatic injection apparatuses which control the administration of therapeutic fluids from a hypodermic syringe to a patient.

During the course of medical therapy and particularly during medical surgery, occasions arise when therapeutic fluids are to be administered to a patient over a relatively extended period of time. At present, infusions of this nature are administered either by repeated injections by hand or by the impercise gravity forced drip method. The prior art discloses some automatic injection devices; however, they are generally bulky, cumbersome and complicated to operate and expensive to manufacture.

The present invention provides an automatic injection device which may be easily operated by a hospital aid and an object of this invention is to provide a completely automatic injection apparatus for injecting therapeutic fluids at a controlled rate directly into a patient.

Another object of this invention is to provide an automatic injection apparatus which is adapted to inject a therapeutic fluid into a patient from a standard medical syringe.

A further object of this invention is to provide a completely automatic injection apparatus which causes a therapeutic fluid to be injected into the body of a patient at a uniform, continuous rate over a predetermined length of time.

Yet still another object of this invention is to provide in an automatic injection apparatus a power source which can travel as the apparatus operates.

These and other objects of this invention will become apparent from the following detailed specification, appended claims and attached drawings in which:

FIGURE 1 is a top plan view of the invention showing the threaded drive shaft coupled to the power source at one end and engaging the pistons of a syringe at the other. i

FIGURE 2 is a side elevation of the apparatus showing the threaded drive shaft having been wormed through a block and into a position of non-advancement.

FIGURE 3 is a fragmentary section taken along lines 3-3 of FIGURE 1 showing the apparatus for mounting the syringe-receiving turntable.

FIGURE 4 is a plan view of the drive motor showing a slide bearing in partial section.

FIGURE 5 is a section taken along lines 5-5 of FIG- URE 2 showing the drive shaft in a non-threaded opening.

FIGURE 6 is a section taken along lines 6-6 of FIG- URE 5 showing the non-threaded portions of the drive shaft in the threaded passageway of the block.

In general, the embodiment of the invention illustrated by the drawings and following description is comprised of an elongated base plate which is adapted to receive a syringe at one end, a threaded and a movably positioned motor at the other end. The threaded drive shaft has a head which seats against the piston portion of a syringe and which moves the piston inwardly into its cooperating cylinder when the drive shaft is rotated by the movably positioned motor. The motor output shaft engages the drive shaft by a coupling arrangement and upon rotation of the coupling, the drive shaft is wormed forwardly through a block which causes the motor to be pulled along the rear portion of the base plate. That is, as the drive shaft rotates the motor is drive shaft in the middle Patented Aug. 22, 1967 pulled in the same direction as the travel of the drive shaft. The rear portion of the base is provided with guide rails which are parallel to each other and disposed on opposite sides of the base plate to provide-a track which is adapted to receive motor slide bearings. The motor may also be mounted on wheels which in turn may be rollably mounted on a track formed by the guide rails.

An electric motor is mounted on the base plate and is provided with a current-carrying extension cord, an offon switch, a gear reduction means which is located within the motor box, an output shaft connected to the gear reduction means and a couple mounted on the output shaft. When the motor is energized, the reduction gears turn the output shaft and the couple at a very slow speed, that is less than five revolutions per minute and preferably approximately one-half revolution per minute. The con:

pling assembly includes a female couple which is mounted on the output shaft that is energized by the gear reducing means. The female couple has a recess or cavity therein and has a slotted wall surface, the recess receiving a cylindrical shoulder which is mounted on a threaded drive shaft while the slotted portion receives locking pins which are mounted upon the collar. The shoulder and locking pins form a male couple. When the male and female couplings are in a locked position, the motor upon energization thereof turns in a direction which tends to keep the coupling locked to the threaded drive shaft. The drive shaft which is threadably received in a block by a threaded passageway is advanced upon the turning of the male coupling unit. While the threaded shaft is advancing through the block, the coupling arrangement causes the motor to be of the base plate.

The threaded drive shaft is provided with a smooth section adjacent both the shaft head and the male coupling element. This non-threaded section of the shaft effectively serves as a stop means for when the threaded portion has wound its way through the block, the engaging threaded portions become disass'ociated and the shaft is prevented from advancing further. The drive shaft may be returned and repositioned for a next forwardthrust by disengaging the male couple from the female couple, raising the smooth portion of the drive shaft through an opening into a clean, non-threaded passageway, pulling the drive shaft back through the clean passageway until only the non-threaded portion of the shaft adjacent the drive head is in engagement therewith, pushing this nonthreaded portion back through the opening and into the threaded passageway of the block, threadably engaging the drive shaft with the threaded passageway and uniting in a locking position the male and female couplings.

The syringe or hypodermic needle which contains a therapeutic fluid is positioned in a pair of clamps which are mounted on a rotating table. It is to be noted that these clamps may be mounted directly on the base plate; however, to provide clamps which receive larger and smaller syringes, a plurality thereof are mounted on a base table which may be turned into a position for receiving most any size syringe. The piston of the syringe when extended is adapted to seat against the drive shaft head and is pushed inwardly into the syringe by this head.

Referring specifically to the drawings, a base plate 10 which is rectangular in the plan view is provided with a pair of opposed guide rails 11 and 12 which are arranged in parallel and on the opposite sides of the elongated base plate 10. Base plate 10 and rails 11 and 12 provide a track along which a movably mounted motor box 13 may slide. Motor box 13 contains a motor and a gear reduction train (which are not shown), a current-carry ing cord 14, and a plurality of slide bearings 15 which are adapted to be received by rails 11 and 12 in a verpulled along the surface portions tically locking position. The track also provides stability in a direction transverse to the direction of the guide rails.

Shaft block 16 which is of the same material as base plate is perpendicularly mounted thereon in a transverse direction at approximately the center thereof. Block 16 is provided with a threaded passageway 17 and a nonthreaded or smooth passageway 18 which are openly connected by an opening 19. Smooth passageway 18 has a diameter which is larger than the outside diameter of threaded passageway 17. Passageway 17 is adapted to receive in a threaded engagement the threaded portion 21 of threaded drive shaft 20. Drive shaft 20 is provided with a drive shaft head 22 being mounted at one end, a non-threaded shaft section 23 being adjacent drive shaft head 22, a threaded drive shaft section 21 extending from section 23 to a second non-threaded drive shaft section 24, and a male coupling arrangement 28 which is connected to second section 24. Non-threaded drive shaft sections 23 and 24 are of a diameter smaller than the inner diameter of threaded shaft section 21.

Motor 13 is adapted to be detachably coupled to drive shaft 20 by means of a coupling arrangement 25. The coupling arrangement is comprised of a female couple 26 which is securely mounted on motor output shaft 27 and a male couple 28 which is securely mounted on threaded drive shaft 20. Male couple 28 has a substantially cylindrical shoulder 29 which perpendicularly and integrally receives locking pins 30. Female coupling 26 is provided with a collar 31 which has located therein a cavity 32 and a slot 33 extending through the wall portions thereof which receive shoulder 29 and locking pins 30 respectively of male coupling 29. It is to be noted that the coupling arrangement may be reversed with male couple 28 being mounted on output shaft 27 and female couple 26 mounted on drive shaft 20.

A turntable arrangement 35 is mounted on base plate 10 at the end and opposite that end of the base plate which receives motor 13. Turret 36 is rotatably mounted on base plate 10 about shaft 37, shaft 37 being rigidly and perpendicularly arranged on base plate 10. A circular flat spring 38 is concentrically mounted on shaft 37 and in counterbore 39. Leaf spring 38 is adapted to frictionally maintain turret 36 in a desired position. A plurality of ball bearings 34 are suitably positioned to reduce friction and to provide a detent type action. A pair of disposed and aligned brackets 40 and 41 are mounted on turret 36 for receiving a syringe 42, syringe 42 being shown in dotted form. A second pair of spaced and aligned brackets 43 and 44 are mounted on turret 36 for receiving a syringe having a different cylindrical diameter. Brackets 43 and 44 may become operable .by rotating turret 36 into a position which axially aligns cylindrical syringe 42 with threaded drive shaft 21.

In operation, syringe 42 having a cylinder 45 and a piston 46 being in an extended position is securely mounted in brackets 40 and 41. Drive head 22 of shaft 20 is placed in a pushing position against piston 46. Threaded shaft 21 is threadably mounted in block 16 and male coupling 28 is received by female coupling 26 in a locking engagement. Upon the rotating of coupling 25 by motor output shaft 27, threaded drive shaft 20 advances through block 16 pushing piston 46 into cylinder 45 and pulling motor 13 along guide rails 11 and 12. The forward movement of the threaded drive shaft 20 and motor 13 is limited in that when threaded portion 21 of drive shaft 20 worms its way through block 16 and becomes threadably disengaged therefrom, block 16 receives non-threaded shaft portion 24 which is not adapted to advance drive shaft 20. To repeat this stroke, female coupling 26 is removed from male coupling 28 and motor 13 is repositioned at one end of base plate 10. Threaded drive shaft 20 is repositioned into a driving position by manually moving non-threaded portion 24 from threaded passageway 17 to non-threaded passageway 18 and sliding threaded shaft 21 the length thereof through non-threaded passageway 18 until non-threaded portion 23 is received by non-threaded passageway 18 whereupon non-threaded portion 23 is placed into threaded passageway 17 and threaded shaft 21 is threadably engaged with threaded passageway 17. Upon uniting male coupling 28 with female coupling 26 and insert ing a fresh syringe 42 in brackets 40 and 41, the apparatus is again adapted to inject a therapeutic fluid into a patient at a uniform rate and over a predetermined length of time.

Since many variants may he obviously introduced into the features of this invention without departing from the spirit and scope thereof, it is to be understood that the accompanying drawings are to be interpreted in an illustrative rather than a limiting sense.

I claim:

1. An apparatus for automatically ejecting a therapeutic fluid from a medical syringe of the cylinder and piston type at a controlled rate comprising:

(a) a base having planar surfaces;

(b) means for firmly attaching said syringe to said base;

(c) a motor slidably mounted on said base, said motor having an output shaft being adapted for rotation;

(d) a block means stationarily mounted on said base and having a threaded passageway extending therethrough;

(e) a threaded drive shaft having a length thereof being in threadable engagement with said threaded passageway and having one end thereof positioned against the exposed end of said piston, said threaded drive shaft upon the rotation thereof being adapted to force said piston into said cylinder; and

(f) means for disengageably connecting the other end of said threaded drive shaft to said motor drive shaft whereby upon a rotation thereof said threaded drive shaft is advanced a distance through said block means thereby pulling said motor a distance along said base.

2. An apparatus for automatically ejecting a therapeutic fluid from a medical syringe of the cylinder and piston type at a controlled rate comprising:

(a) an elongated base plate having planar surfaces and having a pair of disposed guide rails mounted on a surface thereof, said guide rails on said surface cooperating to (form a track;

(b) means for firmly attaching said syringe to a surface of said base;

(c) a motor having slide bearings fixed thereto, said bearings being received by said guide rails thereby adapting said motor to slide along said track, said motor having an output shaft being adapted for rotation;

(d) a block means stationarily mounted on said base and having a threaded passageway extending therethrough;

(e) a threaded drive shaft having a length thereof being in threadable engagement with said threaded passageway and having one end thereof positioned against the exposed end of said piston, said threaded drive shaft upon the rotation thereof being adapted to force said piston into the cylinder; and

(f) means for disengageably connecting the other end of said threaded drive shaft to said motor output shaft whereby upon a rotation thereof said threaded drive shaft is advanced a distance through said block means thereby pulling said motor a distance along said base.

3. An apparatus for automatically ejecting a therapeutic fluid from a medical syringe of the cylinder and piston type at a controlled rate comprising:

(a) a base having planar surfaces;

(b) means for firmly attaching said syringe to said base;

(c) a motor slidably mounted on said base, said motor having an output shaft being adapted for rotation;

(d) a block means stationarily mounted on said base and having a threaded passageway extending therethrough;

(e) a threaded drive shaft having a length thereof being in threadable engagement with said threaded passageway and having one end thereof positioned against the exposed end of said piston, said threaded drive shaft upon the rotation thereof being adapted to force said piston into said cylinder; and

(f) a coupling disengageably connecting the other end of said threaded drive shaft with said end of said motor output shaft, said coupling being comprised of a shoulder mounted on one selected end, said shoulder having a lock pin rigidly attached thereto and a collar mounted on the other end having a slot in the Wall thereof, said collar adapted to internally receive said shoulder and said slot to receive said lock pin whereby upon a rotation of said motor drive shaft said threaded drive is advanced a distance through said block means thereby pulling said motor a distance along said base.

4. An apparatus for automatically ejecting a therapeutic fluid from a medical syringe of the cylinder and piston type at a controlled rate comprising:

(a) an elongated base plate having planar surfaces and having a pair of disposed guide rails mounted on a surface thereof, said guide rails and said surface cooperating to form a track;

(b) means for firmly attaching said syringe to a surface of said base;

(c) a motor having slide hearings fixed thereto, said bearings being received by said guide rails thereby adapting said motor to slide along said track, said motor having an output shaft adapted for rotation:

(d) a block means stationarily mounted on said base and having a threaded passgeway extending therethrough;

(e) a threaded drive shaft having a length thereof being in threadable engagement with said threaded passageway and having one end thereof positioned against the exposed end of said piston, said threaded drive shaft upon the rotation thereof being adapted to force said piston into said cylinder; and

(f) a coupling disengageably connecting the other end of said threaded drive shaft with said end of said motor output shaft, said coupling being comprised of a shoulder mounted on one selected end, said shoulder having a lock pin rigidly attached thereto and a collar mounted on the other end having a slot in the wall thereof, said collar adapted to internally rereceive said shoulder and said slot to receive said lock pin whereby upon a rotation of said motor drive shaft said threaded drive shaft is advanced a distance through said block means thereby pulling said motor a distance along said base.

5. An apparatus for automatically ejecting a therapeutic fluid from a medical syringe of the cylinder and piston type at a controlled rate comprising:

(a) a base having planar surfaces;

(b) means for firmly attaching said syringe to said base; I

(c) a motor slidably mounted on said base, said motor having a drive shaft being adapted for rotation;

(d) a block means stationarily mounted on said base and having a threaded passageway extending therethrough;

(e) a threaded drive shaft having a drive shaft head at one end positioned against the exposed end of said piston, a power receiving end and a shaft, said shaft having a smooth portion extending a distance from said power receiving end being greater than the length of said threaded passageway in said block means and a threaded portion extending from said smooth portion and having an inner diameter being greater than the diameter of said smooth portion,

said threaded drive shaft being adapted for rotation and advancement when said threaded portion is threadably received by said threaded passageway and being adapted for rotation only when said smooth portion resides in said threaded passageway; and

(f) means for disengageably connecting the other end of said threaded drive shaft to said motor output shaft whereby upon a rotation thereof said threaded drive shaft is advanced a distance through said block means thereby pulling said motor a distance along said base.

6. An apparatus for automatically ejecting a therapeutic fluid from a medical syringe of the cylinder and piston type at a controlled rate comprising:

(a) a base having planar surfaces;

(b) means for firmly attaching said syringe to said base;

(c) a motor slidably mounted on said base, said motor having a drive shaft being adapted for rotation;

(d) a block stationarily mounted on said base, said block having a threaded passageway and a smooth passageway extending therethrough, said passageways being axially parallel and being connected by an opening extending the length thereof, said smooth passageway having a diameter being greater than the outer diameter of said threaded passageway;

(e) a threaded drive shaft having a drive shaft head at one end positioned against the exposed end of said piston, a power receiving end and a shaft, said shaft having a first smooth portion extending a distance from said power receiving end being greater than the length of said passageway in said block means, asecond smooth portion extending a distance from said drive shaft head being greater than the length of said threaded passageway and a threaded portion linking said first and said second smooth portions and having an inner diameter being greater than the diameter of each smooth portion, said piston drive shaft being adapted for rotation and advancement when said threaded portion is threadably received by said threaded passageway; and

(f) means for disengageably connecting the other end of said threaded drive shaft to said motor output shaft whereby upon a rotation thereof said threaded drive shaft is advanced a distance through said block means thereby pulling said motor a distance along said base.

7. An apparatus for automatically ejecting a therapeutic fluid from a medical syringe of the cylinder and piston type at a controlled rate comprising:

(a) an elongated base plate having planar surfaces and having a pair of disposed guide rails mounted on a surface thereof, said guide rails and said sur face cooperating to form a track;

(b) means for firmly attaching said syringe to a surface of said base;

(c) a motor having slide bearings fixed thereto, said bearings being received by said guide rails thereby adapting said motor o slide along said track, said motor having an output shaft being adapted for rotation;

(d) a block means stationarily mounted on said base and having a threaded passageway extending therethrough;

(e) a threaded drive shaft having a drive shaft head at one end positioned against the exposed end of said piston, a power receiving end and a shaft, said shaft having a smooth portion extending a distance from said power receiving end being greater than the length of said threaded passageway in said block means and a threaded portion extending from said smooth portion and having an inner diameter being greater than the diameter of said smooth portion, said threaded drive shaft being adapted for rotation and advancement when said threaded portion is threadably received by said threaded passageway and being adapted for rotation and advancement when said threaded portion is threadably received by said threaded passageway and being adapted for rotation only when said smooth portion resides in said threaded passageway; and

(f) a coupling disengageably connecting the other end of said threaded drive shaft with said end of said motor output shaft, said coupling being comprised of a shoulder mounted on one selected end, said power receiving end being greater than the length of said threaded passageway in said block means, a second smooth portion extending a distance from said piston pushing end and being greater than the length of said threaded passageway and a threaded portion linking said first and second smooth portions and having an inner diameter being greater than the diameter of each smooth portion, said piston drive shaft being adapted for rotation and advancement when said threaded portion is threadably received shoulder having a lock pin rigidly attached thereto 10 by said threaded passageway; and and a collar mounted on the other end having a slot (f) a coupling disengageably connecting the other end in the walls thereof, said collar adapted to internally of said threaded drive shaft with said end of said receive said shoulder and said slot to receive said motor output shaft, said coupling being comprised lock pin thereby upon a rotation of aid moto driv of a shoulder mounted on one selected end, said shaft said threaded drive shaft is advanced a disshoulder having a lock pin rigidly attached thereto tance along said block means thereby pulling said and a 6011 mounted 011 file other end having a motor a distance along said base. slot in the Walls thereof, said collar adapted to in- 8- An apparatus for automatically ejecting a therapeuternally receive said shoulder and said slot to retic fluid from a medical syringe of the cylinder and pis- Ceive Said 106k P whereby upon rotation of Said ton type at a controlled rate comprising; motor drive shaft said threaded drive shaft is ad- (a) an elongated base plate having planar s f vanced a distance through'said block means thereby and having a pair of disposed guide rails mounted Pulling Said motor a distance along Said baseon a surface thereof, said guide rails and said sur- The apparatus of Claim 8 wherein Said a s for face cooperating to for a t k; firmly attaching said syringe to said base is comprised of a shaft being integral with and perpendicular to said base, a turntable rotatably mounted on said shaft, and a plurality of pairs of clamps, each pair being rigidly mounted on said turntable and axially aligned whereby each pair of said clamps is adapted to receive a syringe.

(b) means for firmly attaching said syringe to a surface of said base;

(c) a motor having slide bearings fixed thereto, said bearings being received by said guide rails thereby adapting said motor to slide along said track, said motor having an output shaft adapted for rotation;

(d) a block stationarily mounted on said base, said block having a threaded passageway and a smooth passageway extending therethrough, said passage- References Cited UNITED STATES PATENTS ways being axially parallel and being connected by gigg "5 52 an opening extending the length thereof, said smooth 561236 11/1964 figgg passageway having a diameter being greater than n the outer diameter of said threaded passageway; FOREIGN PATENTS (e) a threaded drive shaft having a drive shaft head 4,718 2 2 Great Britain.

RICHARD A. GAUDET, Primary Examiner.

D. L. BAKER, Assistant Examiner.

position again-st the exposed end of said piston, a power receiving end and a shaft, said shaft having a first smooth portion extending a distance from said 

1. AN APPARATUS FOR AUTOMATICALLY EJECTING A THERAPEUTIC FLUID FROM A MEDICAL SYRINGE OF THE CYLINDER AND PISTON TYPE AT A CONTROLLED RATE COMPRISING: (A) A BASE HAVING PLANAR SURFACES; (B) MEANS FOR FIRMLY ATTACHING SAID SYRINGE TO SAID BASE; (C) A MOTOR SLIDABLY MOUNTED ON SAID BASE, SAID MOTOR HAVING AN OUTPUT SHAFT BEING ADAPTED FOR ROTATION; (D) A BLOCK MEANS STATIONARILY MOUNTED ON SAID BASE AND HAVING A THREADED PASSAGEWAY EXTENDING THERETHROUGH; (E) A THREADED DRIVE SHAFT HAVING A LENGTH THEREOF BEING IN THREADABLE ENGAGEMENT WITH SAID THREADED 